Thermal synthesis and hydrolysis of polyglyceric acid (original) (raw)
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Fibers and Polymers, 2017
Polyglycolic acid (PGA) was successfully synthesized via solution and melt/solid polycondensations. PGA was synthesized by solution polymerization under vacuum by using diphenylsulfone as solvent and methanesulfonic acid as catalyst and the inherent viscosity of resultant PGA was 0.2 dl/g. The intrinsic viscosity was obtained up to 0.35 dl/g of the PGA synthesized by melt/solid polycondensation. Whereas, PGA synthesized by longer hours of SSP was insoluble in most of the known solvents, which might have higher molecular weight as well as crystallinity. Crystallographic structure of PGA was confirmed by XRD and the resulting PGA polymer was similar in thermal degradation to that of commercially available polyglycolide (Kuredux), synthesized by ring opening polymerization. Both PGAs were characterized for thermal decomposition kinetic studies using thermaogravimetric analysis (TGA), to investigate the effect of end-group and molecular weight on thermal degradation behavior. TGA was performed at 6 different heating rates from 5 to 50 o C/min and data was analyzed by three different approaches to obtain activation energy. Activation energy from Kissinger's approach was 112 kJ/ mol for lab synthesized PGA and 119 kJ/mol for Kuredux, whereas from Flynn and Wall's method, it was observed as 115 kJ/ mol and 121 kJ/mol for solution-polymerized PGA and Kuredux respectively and activation energies calculated from dynamic experiment method was also comparable of both PGAs. From dynamic experiment method linearity curve starts as low as 1 % decomposition and continues as high as 97 % with decomposition temperature ranges 219 to 380 o C for PGA and 230 to 406 o C for Kuredux. Consequently, Kissinger's method, Flynn and Walls method and the dynamic experiment method reveal that the thermal decomposition behavior of polyglycolic acids and polyglycolide is similar, regardless of end groups and synthetic routes which is supposed to be random chain cession.
LWT, 2021
Monoacylglycerols (MAG) containing polyunsaturated fatty acids (PUFA) have been synthesized by glycerolysis of anchovy oil using Lipozyme RM-IM in a solvent-free system. The experimental conditions, reaction temperature, substrate molar ratio (glycerol/triacylglycerol, Gly/TAG) and enzyme concentration were studied. A response surface methodology was employed to analyze the effect of the individual variables on MAG production and oxidative stability with respect to induction time. The operating conditions that simultaneously optimized MAG yields and oxidative stability were a reaction temperature of 40 • C, a Gly/TAG molar ratio of 2:1 and 6% enzyme load. The yield obtained was 20.34% of MAG (with 12.12% of 2-MAG) and an induction time of 1.88 h.
Bioresource …, 2010
The present study demonstrates biopolymer production by in situ bio-based dimerization of fatty acids by microorganism isolated from marine sediments. Microbial isolate grown in Zobell medium in the presence of triglycerides for the period of 24-240 h at 37°C, hydrolyze the applied triglycerides and sequentially dimerized the hydrolyzed products and subsequently polymerized and transformed to a biopolymer having appreciable adhesive properties. Physical (nature, odour, stickyness and tensile strength), chemical (instrumentation) and biochemical (cell free broth) methods of analyses carried out provided the hypotheses involved in the formation of the product as well as the nature of the product formed. Results revealed, lipolytic enzymes released during initial period of growth and the biosurfactant production during later period, respectively, hydrolyze the applied triglycerides and initiate the dimerization and further accelerated when the incubation period extended. The existence and the non-existence of in situ hydrolysis of various triglycerides followed by dimerization and polymerization and the mechanism of transformation of triglycerides to biopolymer are discussed in detail.
Hydroxymethylation and polymerization of plant oil triglycerides
Journal of Applied Polymer Science, 2004
The ene reaction between plant oil triglycerides (such as soybean and sunflower oils) and paraformaldehyde was used to introduce a homoallylic hydroxyl functionality on the triglyceride. Paraformaldehyde and triglyceride were reacted in the presence of a Lewis acid catalyst, ethylaluminum dichloride, and hydroxymethyl derivatives were obtained at yields of 42 and 55% for sunflower oil and soybean oil, respectively. In the next step, hydroxymethyl products were reacted with maleic anhydride at 100°C to produce the maleate half esters. The average number of maleate groups per triglycerides was found to be 1.7 for soybean oil and 1.3 for sunflower oil. In the final step, the free-radical-initiated copolymerization of the maleinized triglycerides with styrene produced rigid polymers. Characterization of new monomers and polymers was done by 1 H-NMR, 13 C-NMR, and infrared and mass spectrometries. The swelling behavior of the crosslinked network polymers was determined in different solvents. The glass-transition temperature of the cured resin was also determined by differential scanning calorimetry to be 40°C for soybeanbased polymer and 30°C for sunflower-based polymer.
Energy-rich glyceric acid oxygen esters: Implications for the origin of glycolysis
Origins of Life and Evolution of the Biosphere, 1990
The apparent Gibbs free energy change of hydrolysis (AG °', pH 7) of the 2-and 3-O-glyceroyl esters of 2-and 3-O-L-glyceroyl-L-glyceric acid methyl ester were measured at 25 °C. The 2-and 3glyceroyl esters were found to be 'energy-rich' with AG °' values of-9.1 kcal mol-I and 7.8 kcal mol, respectively. This result indicates that the analogous 2-and 3-glyceroyl esters of polyglyceric acid are also 'energy-rich' and, therefore, could have acted as an energy source for primitive phosphoanhydride synthesis.
Synthesis of designer triglycerides by enzymatic acidolysis
Biotechnology reports (Amsterdam, Netherlands), 2018
Enzymatic acidolysis process was developed for modification of fully hydrogenated soybean oil (FHSO) by incorporation of caprylic acid, a medium chain fatty acid. Immobilized sn-1,3 specific lipase PyLip was used to modify FHSO to produce a new fat with improved physico-chemical and functional properties. PyLip mediated acidolysis resulted in 88% reduction of substrate triglycerides and 45.16% incorporation of caprylic acid in FHSO at molar ratio of 1:3 of FHSO and caprylic acid in 60 min reaction time. HPLC analysis revealed formation of mono-substituted and di-substituted TAGs post enzymatic acidolysis. Physical properties of synthesized lipid were studied using DSC and XRD and considerable change was observed in the final product compared to the starting material. The present study reports a faster acidolysis process in the presence of solvent enhancing the modification of FHSO with caprylic acid and having no side products formation (monoglycerides and diglycerides) making the e...
2006
Precursor compounds for abiotic proto cellular membranes are necessary for the origin of life. Amphipathic compounds such as fatty acids and acyl glycerols are important candidates for micelle/bilayer/vesicle formation. Two sets of experiments were conducted to study dehydration reactions of model lipid precursors in aqueous media to form acyl polyols and wax esters, and to evaluate the stability and reactions of the products at elevated temperatures. In the first set, mixtures of n-nonadecanoic acid and ethylene glycol in water, with and without oxalic acid, were heated at discrete temperatures from 150 • C to 300 • C for 72 h. The products were typically alkyl alkanoates, ethylene glycolyl alkanoates, ethylene glycolyl bis-alkanoates and alkanols. The condensation products had maximum yields between 150 • C and 250 • C, and were detectable and thus stable under hydrothermal conditions to temperatures <300 • C. In the second set of experiments, mixtures of n-heptanoic acid and glycerol were heated using the same experimental conditions, with and without oxalic acid, between 100 • C and 250 • C. The main condensation products were two isomers each of monoacylglycerols and diacylglycerols at all temperatures, as well as minor amounts of the fatty acid anhydride and methyl ester. The yield of glyceryl monoheptanoates generally increased with increasing temperature and glyceryl diheptanoates decreased noticeably with increasing temperature. The results indicate that condensation reactions and abiotic synthesis of organic lipid compounds under hydrothermal conditions occur easily, provided precursor concentrations are sufficiently high.
Glycerolysis of Poly(lactic acid) as a Way to Extend the “Life Cycle” of This Material
Polymers, 2019
The article concerns the use of glycerolysis reaction as an alternative method of processing post-production and post-consumer waste from poly(lactic acid) (PLA). Management of waste is a very important issue from an environmental protection and economic point of view. Extending the “life cycle” of PLA is extremely important because it allows to make the most of this material. It also limits economic losses resulting from its disposal in the biodegradation process at the same time. This paper presents a method of glycerolysis of poly(lactic acid) waste using various amounts of anhydrous glycerol (mass ratio from 0.3 to 0.5 parts by weight of glycerol per 1.0 part by weight of PLA). This process was also carried out for pure, unmodified PLA Ingeo® (from NatureWorks) to compare the obtained results. The six liquid oligomeric polyhydric alcohols were obtained as a result of the synthesis. Then, they were subjected to physicochemical tests such as determination of color, smell, density,...